Meters are often attached to pipelines to measure the volume of fluid flowing past a point within the pipeline in both residential and commercial applications. The pipeline typically includes a meter bar with an inlet and outlet swivel fitting to facilitate connection of the meter to the pipeline.
Each swivel fitting includes a threaded nut and an annular flange. The threaded nuts engage complementary threads on the meter to secure the meter to the meter bar. A gasket (not shown) is disposed between the flange on the inlet/outlet swivel fittings and respective inlet/outlet ports of the meter to provide a fluid tight seal between the meter and the meter bar.
Many municipalities require gas meters to be changed periodically for preventive maintenance. In prior art systems, the flow of gas within the pipeline had to be shut off to allow changing of the meter. As a result, pilot lights downstream of the meter would be extinguished.
To relight the pilot lights, the municipalities would typically schedule appointments with customer to allow access to the home or business. Scheduling these types of visits introduces costly inefficiencies into the change out process.
Attempts have been made to provide a change out mechanism that does not interrupt the flow of fluid within the pipeline. In one attempt, a complex tool was designed to bypass the flow of fluid during meter change out. In this tool, the gasket retraction process is performed blindly inside the tool. This creates a problem because the elastomeric gasket that seals the meter to the swivel adheres to both the meter and swivel surfaces, which causes difficulty in separation and removal. Because the retraction process is performed blindly, it is difficult to ensure that the gasket will remain with the meter as it is removed. If the gasket is not retracted with the meter, the gas must be shutoff to allow the removal of the tool to gain access to the gasket for its subsequent removal.
Accordingly, there is a need in the industry for improved devices and methods for changing out meters in a pipeline without interrupting the flow of fluid within the pipeline.